(1) Field of the Invention
The present invention pertains to a microsurgical laser probe used primarily in ophthalmic surgery where the probe provides both laser light and illumination light to a surgical site. More specifically, the laser probe of the invention has a dual core optic fiber that transmits both laser light and illumination light to a surgical site. A center core of the optic fiber transmits the laser light through the fiber and emits the laser light at the surgical site. The center core of the fiber is surrounded by an outer fiber core. The outer core transmits illumination light through the fiber and emits the illumination light at the surgical site.
(2) Description of the Related Art
Laser endoprobes or microsurgical probes and white light illumination probes have been employed in performing ophthalmic surgery procedures for many years. Until the early 1980's, laser probes and illumination probes were separate and independent instruments. Examples of these are disclosed in the U.S. Pat. No. 7,060,028 and U.S. Pat. No. 4,607,622.
In 1986, the Mir Ali U.S. Pat. No. 4,583,526 disclosed a handpiece that had a carbon dioxide laser and an illumination light source traveling in parallel. The U.S. patents of Easley et al. U.S. Pat. No. 5,275,593 and U.S. Pat. No. 5,356,407 also disclose instruments that combined both laser and illumination fibers in the same probe. Presently, almost all of the major ophthalmic surgery instrument manufacturing companies have a line of illuminated laser probes. These probes work on the basic premise that two or more fibers are fed down the length of a tubular tip at the front of an instrument. The distal ends of the fibers are positioned adjacent to the distal end of the tip. The proximal end of one of the fibers is connected to a laser light source, and the proximal end of the other fiber is connected to an illumination light source.
As ophthalmic illumination sources have improved, the size and the number of optic fibers that are used in microsurgical instruments has decreased. In 2004, Synergetics, Inc. developed a light source capable of coaxially aligning a laser light and a white light illumination path so that both would be able to travel down a single fiber. This allowed for the use of a single optic fiber that would simultaneously provide both illumination light and laser light at the surgical site.
However, there were problems associated with using a single optic fiber for the transmission of both illumination light and laser light to the surgical site. It was observed that the light emitted from the optic fiber distal end would have the same divergence angle as the light delivered by the light source to the optic fiber proximal end. This meant that the area of illumination at the surgical site would be directly proportional to the size of the laser light spot at the surgical site. For example, the illumination light divergence angle at the distal end of the optic fiber would normally be 30 degrees off the center axis, and the laser light divergence angle at the distal end of the optic fiber would normally be 8 degrees off the axis. When the microsurgical probe distal end tip would be positioned close enough to the surgical site to get a laser light spot sized small enough for a desired burn, the area of illumination would be very small.
Illuminated laser probes have been designed according to two methods to compensate for this shortcoming. Probes have been designed with two staggered optic fibers, with the distal end of the illumination optic fiber being spaced back from the distal end of the laser optic fiber. This design would provide a larger area of illumination at the surgical site, but would produce a shadow in the illumination area where the illumination light is blocked by the distal end of the laser optic fiber. The other solution was to make the illumination optic fiber a wide field fiber. This was done through the use of a cone-shaped lens such as that disclosed in the U.S. Pat. No. 6,829,411, or the use of optical films, or an emulsion of glass spheres or balls. However, each of these would also produce a shadow of the laser optic fiber. Furthermore, the single optic fiber design would not allow for any of these options because it would scatter all of the illumination light and laser light transmitted equally.